Apparatus for stretching and smoothing a natural tobacco leaf

ABSTRACT

An apparatus for stretching and smoothing tobacco leaves comprising an intermittently advanced, air permeable, stretchable conveyor belt for carrying leaves from a receiving station to a smoothing station to a stretching station. A moist leaf placed and aligned on the belt at the receiving station, and held thereon by suction through the belt, is advanced to the smoothing station where it is clamped by its central vein and subjected to diverging air currents that flutter the edges of the leaf outwardly. Suction is then reapplied to hold the leaf and it is advanced to the stretching station where the belt is transversely stretched to thereby stretch the leaf as well.

United States Patent 13,612,067

[72] Inventor N115 wlunbt'll'll 1,981,470 1 l/1934 Rundell et a] 131/123spang a, SWQdEIl 2,179,644 1 H1939 Rundell 131/123 [21] Appl. No.853,418 2,180,368 11/1939 Rundell et a1... 131/124 [22] Filed Aug. 27,1969 2,212,520 8/1940 Gwinn et a] 131/123 [1);] f i: 1: PrimaryExaminer-Sarnuel Koren 1 St H mm fi Sweden Assistant Examiner-J. F.Pitrelli Priority Sept. 9, 1968, No 4 1968 Attorney Sughrue, Rothwell,Mron, Zrnn & MacPeak [33] Sweden [31] 12,116/68 and 14,923/68 [54]APPARATUS FOR STRETCHING AND SMOOTHING A NATURAL TOBACCO LEAF 8 8Drawing Flgs' ABSTRACT: An apparatus for stretching and smoothing [5 2]US. Cl 131/147 R, tobacco leaves comprising an intermittently advanced,air 131/123, 131/131 permeable, stretchable conveyor belt for carryingleaves from 1 fi 0 1 a receiving station to a smoothing station to astretching sta- A24b 05/14 tion. A moist leaf placed and aligned on thebelt at the receiv- [50] Field ofSearch 131/123,

ing station, and held thereon by suction through the belt, is ad- 125, 1148 vanced to the smoothing station where it is clamped by its cen-References Cited tral vein and subjected to diverging air currents thatflutter the edges of the leaf outwardly. Suction is then reapplied tohold UNITED STATES PATENTS the leaf and it is advanced to the stretchingstation where the 563,656 7/1896 Caner 131/147 belt is transverselystretched to thereby stretch the leaf as well.

e M Y ,1 I

16 I 1 /17 N 1 I J r r B I S" Q 3 PATENTEU um I 2 I97! SHEEI 3 BF 3APPARATUS FOR STRETCIIING ANDfSMOOTI-IING A NATURAL TOBACCO LEAFBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to an apparatus for stretching and smoothing a natural tobaccoleaf and comprises airflow members adapted to expose the tobacco leaffixed on a leaf support to an airstream directed from the central veinof the leaf to the edges thereof and-suction means for retaining theleafin an expanded condition after the stretching step.

2. Description of the-Prior Art In known apparatuses which have beencoupled together with stripping machines the demands on stretching theleaf are low and therefore the leaf, afier afirst stretching treatment,is transferred in a free state to a suction conveyor or the like forfurther advance to the stripping -knives. Here the leaves rapidly regaina relatively creasedcon'dition and must,-if they are to be fed to meansfor cutting out wrappers for cigars, be inserted into a smoothing devicecomprisingrotating brushes or suction cloths which smooth the leaf bymechanical action. However, if an effective smoothing shall be broughtabout, the action of these devices normally causes damage to the highlyvulnerable, moistleaves, and in addition, his not possible to bringabout a flattening of leaf portions, bent inwardly under the leaf.

SUMMARY OF THE/INVENTION This invention provides an apparatus-forstretching a tobacco leaf and retaining it stretched during the entirestretching operation until final working or storing while'totallyavoiding the risk of the leaf becoming damaged, irrespective of howvarious portions of the leaf are folded onto one another.

BRIEF DESCRIPTION OF TI-IE DRAWINGS Further objects and advantages ofthe invention will become apparent from the following descriptionconsidered in connection-with the accompanying drawings which form partof this specification and in which:

FIG. I shows an exemplary embodiment of the apparatus viewed from abovewith certain portions removed for the sake of clarity, I

FIG. 2 shows a section through the apparatus of FIG. '1, taken along theline IIII,

FIG. 3 shows a section through the apparatus of FIG. 1, taken along theline IIIIII,

FIG. 4 shows a section through the apparatus of FIG. '1, taken along theline IV-IV,

FIG. 5 shows a section through the apparatus of FIG. 1 taken along theline V--V,

FIG. 6 is a side view of an apparatus for stretching natural tobaccoleaves coupled to a stripping machine,

FIG. 7 is a top view of the apparatus of FIG. 6 and FIG. 8 is asectional view following the line VIII-VIII of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT The embodiment shown in thedrawings comprises three stations A, B and C, of which stations A and Billustrate the basic invention and which may be utilized as such withoutthe station C for feeding stretched leaves to a stemming machine, forexample. Station C being utilized in those cases wherev a strongstretching of the tobaccoleaf already flattened in the station B isrequired. The expression tobacco leaf used herein is intended to meanboth a nonstemmed natural tobacco leaf, Le. a leaf having a centralvein, and a leaf half or other major part of a natural tobacco leaf,such as a cigar binder or a wrapper.

The apparatus shown in FIGS. 1 to 5 is provided with an airpermeablebelt 1 of at least transversely stretchable material, such as aperforated rubber belt, a woven belt or the like. If

the station, C is not utilized, the belt need not be stretchable, as

will become evident later, but may consist of a perforated steel band oran air-permeable belt of other nonstretchable material. The belt I isguided over rollers of which roller 2 only is shown. Roller 2 is drivenin the direction of the arrow, FIG. 2, from a power source not shown,and thus the upper part of the belt 1 moves in the direction of thearrow shown at station A, FIG. 1. In the embodiment shown, the device isdriven intermittently in such a manner that a tobacco leaf 3 during restof the belt is placed on the belt 1 at the station A and thereafter 'andthe stub axles of the rollers are mounted in the walls of a vacuum box 7(FIG. 4) and in a counterpressure rail 8 extending in the longitudinaldirection of the belt IJVacuum box 7 is connected to a vacuum source,not shown, through a suction pipe 9 provided with a throttle valve I0.

The rollers 4 at station C are mounted in the walls of a vacuum boxll,which through a suction pipe 12 is in connection with a-vacuumsource,not shown.

In orderto obtain" an additional stretching of tobacco leaf 3 at stationC, the belt l-in the embodiment shown is guided laterally. Theedge'portions of the belt I are provided with a longitudinally extendingholding means 13 in the shape of bul- 'bous projections or'the like onwhich guide pins 14 are secured. The guide pins 14 are guided in grooves15 fonned in two guide rails 16. On both sides of the belt I, thegrooves 15 extend parallel to one another and between stations A and Bare spaced apart a' first distance from one another, whereas at stationC, the distance is'increased so as to cause a transverse stretching ofthe belt I.

Disposed at the station B over the upper part of the beltl is a devicefor stretching the leaf. In the embodiment shown, the leafstretchingdevice consists of a suction box 17, which is wholly opentowards the belt I. On both sides of the belt I, the suction box '17 isequipped with two suction tubes l8, 19, which are provided with throttlevalves 20, 2] (FIG. 4). By means of a tie rod 22, the suction box 17 canbe lifted and lowered. The tie rod 22 has 'its upper end connected toone end of a lever 23 (FIG. 4) which is fixed at 24 and the other end'ofwhich carries a cam follower 25. The follower 25 is forced by a pressurespring 26 positioned between the lever 23 and a fixed bearing 27 againsta cam 28 which is mounted on a shaft 29 driven from a power source notshown. The top plate of the suction box 17 on which the tie 'rod 22 isrigidly secured, is further equipped with two guide bars 30 running instationary guides 31, th'e'purpose of which to guide the box 17 duringthe movement thereof. Mounted on the under side of the box plate is apressure rail 32 facing the counterpressure rail 8 (FIGS. 2 and 4) andpreferably made of some resilient material such as rubber, and which inthe working position of the suction box 17, shown in FIG. 4, bearsagainst the counterpressure rail 8. In' the embodiment shown, the boxplate is further formed with inlet suction openings 33 locatedapproximately in the center line of the box 17 and disposedsubstantially over the entire length of the box 17 in parallel with thedirection of feed of the belt. The sidewalls of the box 17 extending inthe longitudinal direction of the belt 1 fonn elongated suction nozzles34. When the throttle valves 20, 21 are open, air is sucked through theholes 33 and the noules 34 into the tubes 18 and 19 and an airstream iscreated which substantially is directed, in the embodiment shown, fromthe central vein 35 of the tobacco leaf 3.

The apparatus shown operates in the following manner. A moistenednatural tobacco leaf which is to be stretched is a station A laid on thebelt 1 when at rest, markings 36 arranged on the belt serving as guidepoints for centering the central vein 35 of the leaf 3. This centrallocating operation is not particularly critical. By means of the vacuumbox 5, an air stream is continuously drawn through the belt 1 and theleaf not yet flattened is retained in correct position by suction.During this step, the suction box 17 in station B is in its loweredposition, and the throttle valves 10, 20 and 21 have the positions shownin FIG. 4. By means of a conventional control mechanism, not shown, thethrottle valve is thereupon opened and the throttle valves 20 and 21 areclosed, whereby a processed leaf is retained by suction on the belt 1 atstation B. Shaft 29 is thereafter rotated and the cam 28 rotates in thedirection of the arrow (FIG. 4), whereby the lever 23 is turnedclockwise and raises the tie rod 22 and thus, the suction box 17 fromthe belt, e.g. 1 cm.

Thereafter, the conventional driving mechanism not shown drives roller 2and belt I one step forwards, so that the tobacco leaf 3 fed in atstation A is advanced below the suction box 17 at station B, whereuponthe belt 1 is stopped and the box 17 lowered to the position shown inFIG. 4. The leaf 3 will thereby have the central vein 35 clamped betweenthe rail 8 and the rail 32, the central vein 35 being retained firmly inthe clamped position. Simultaneously, throttle valves 20 and 21 areopened and throttle valve 10 is closed and the leaf portions on eitherside of the vein 35 are each exposed to a strong airstream directedoutwardly. By these two airstreams, the two leaf halves are caused toflutter, so that all tuckings and foldings are straightened out and insuch a manner that a stretching from the central vein 35 towards theedges is obtained. After the stretching has been completed within afirst time interval of some seconds, the automatic control device, notshown, of the apparatus opens the throttle valve 10 during a second timeinterval the throttle valves 20 and 21 being closed simultaneouslytherewith or immediately thereafter. The shaft 29 is caused to rotate,and the cycle described earlier for lifting the suction box 17 andfeeding a leaf recently put on at the station A into station B isrepeated. The stretched leaf 3 at the station B is conveyed whileretained by suction on the belt 1 to station C. Due to the fact that thespacing between the grooves increases between stations B and C, the belt1 will be expanded laterally and, thus, also leaf 3 will be stretchedlaterally.

As already mentioned, the station C is utilized only when a very strongstretching of the leaf is required. It is obvious that apparatus can bemodified in various manner without departing from the inventive idea.Thus, it is possible for example, during the stretching of the leaf atthe station B to use the vacuum box 7 as a source of compressed air inorder to treat the underside of the leaf 3 also by means of anairstream. Further the belt 1 can be provided with fixing members of theclamp type, by means of which one end of the central vein ismechanically secured onto the belt, whereby the marking 36 and in somecases also the vacuum box 5 can be dispensed with.

The apparatus may also be driven continuously, in which case a constantspacing always exists between the belt 1 and the suction box 17 in orderto allow the leaves to pass through freely. Of course, in this case, themechanism for lifting and lowering the suction box to the open positionand the position substantially sealing against the belt 1 is notrequired. In both cases where a stretching station C is used, it isfurther possible instead of stretchable belts to use belts of metal orrigid plastic consisting of longitudinally extending discs displaceabletransversally in relation to one another.

The apparatus shown in FIGS. 6 to 8 is provided with a deposit table 37for tobacco leaves, which in the present case are nonstemmed, e.g.retaining their central vein. The table 37 which is intended to rendereasier correct feeding into the stretching apparatus is formed with acentral row of suction holes 38. The table 37 is formed as a suction boxand communicates via a conduit 39 with a suction source not shown here.The tobacco leaf 3 is manually deposited on the table 37 with itscentral vein over the suction holes 38. The leaf is thereby retained inposition and conveyed onto a conveyor belt 40. The conveyor belt 40 islaid over two-belt pulleys 41, 43 of which at least one is driven. Thebelt 40 passes through a groove 44 in a box 45 which supplies compressedair to a blowpipe table 46. The blowpipe table 46 is formed with acentral groove into which the upper portion of the conveyor belt 40 isadvanced. In the embodiment shown, the upper, supporting surface of thebelt 40 is located slightly above the surface of the table 46. Twopressure belts 47, 48 parallel to one another and to the belt 40cooperate with the upper portion of the belt 40 which is aligned withthe row of suction holes 38. The pressure belts are spaced from oneanother by such a distance and cooperate with the belt 40 in such amanner, that the central vein of a tobacco leaf 3 fed from the table 37will be situated between the belts 47 and 48 and clamped rigidly againstthe belt 40. The belts 47, 48 are laid over belt pulleys 49, 50, ofwhich pulley 49 is driven in the direction of the arrow by means ofdriving members not shown here.

A second, upper blowpipe table 51 is disposed parallel to and spacedfrom the first, lower blowpipe table 46 and connected to an upper box 52which supplies compressed air. The compressed air is supplied to thelower box 45 through a conduit 53 which is connected to a source forcompressed air not shown and preferably controllable so that thequantity of supplied compressed air can be varied. The box 52 forcompressed air is connected via a conduit 54 to a source of compressednot shown which may be the same as that for the box 45. Preferably,control means are disposed between the source for compressed air and thetwo boxes 45 and 52 such that the quantities of air supplied to each ofthe boxes can be adjusted independently of one another.

Blowing openings 55 are formed in the blowpipe tables 46 and SI at leastwithin the zone which is occupied by an introduced tobacco leaf 2, saidblowing openings producing airstreams directed from the central vein ofthe leaf outwardly towards the edges of the leaf and acting on both theunderside and the upper side of the leaf. As will be seen best from FIG.8 the openings 55 have the shape of channels directed from the centralline of the tables 46, 51, respectively, to the outer edges thereof.When the source (not shown) for the compressed air is in operation, atobacco leaf, which has been fed from the table 37 onto the continuouslyoperating conveyors 40 and 47, 48 will thus be introduced between theblowpipe tables 46 and 51 and be exposed to two air streams, one fromthe blowpipe table 46 acting on the under side of the tobacco leaf andone from the blowpipe table 51 acting on the upper or top side of saidleaf. The airstream from the blow pipe table 46 is divided into twopartial streams each of which acts from the central vein retained byclamping between the conveyor belts towards the edges of the leaf, andthe airstream from the blowpipe table 51 is divided into two similarairstreams. Thereby the leaf will be strongly fluttered and stretched inthe desired manner. Even when the leaf is folded strongly andnonflexible a smoothing and stretching will be obtained by theairstreams which are adjustable independently of one another and whichact both on the upper side and the under side of the leaf.

The tobacco leaf 3 is fed continuously through the leaf stretchingapparatus and discharged therefrom onto a conveyor consisting of twoperforated or air-permeable conveyor belts 56, 57, which are laid overconveyor rollers 42 and 68 of which the roller 68 is driven from adriving device not shown. The conveyor belts 56, 57 form betweenthemselves a gap 58 for the conveyor belts 47, 48 and for strippingknives cooperating with one another for destemming the tobacco leaf,i.e. for cutting away the central vein thereof. A suction box 59 whichthrough a conduit 60 communicates with a suction source not showncooperates and is situated below the upper portions of the conveyorbelts 56, 57. The stripping knives consist of two lower, driven circularknives 61, 62 spaced from one another by a distance approximatelycorresponding to the breadth of the stem of the tobacco leaf. A drivencircular feeder knife 63 is positioned above and cooperates with thecircular knives 61, 62. The knives rotate in the shown directions. whenthe stretched tobacco leaf 3 is discharged from the blowpipe tables 46,51 by the conveyor belts 40, 47 48 it is fixed by suction in itsstretched state onto the conveyor belts 56, 57 which are advanced in thedirection of the arrow shown in FIG. 7 and with the same speed as thebelts 40, 47, 48. When the central vein of the leaf is introducedbetween knives 61, 62, 63 it is continuously away, leaving two stretchedleaf halves remaining on the conveyor 56, 57, as is shown at the rightin FIG. 7 which leaf halves can be directly transferred by means notshown here to, e.g. a cigar wrapping machine.

What is claimed is:

1. An apparatus for stretching and smoothing a natural tobacco leafincluding airflow members adapted to expose the leaf fixed on a leafsupport to an airstream directed from the central vein of the tobaccoleaf towards the edges thereof and suction members for retaining theleaf in expanded condition after the stretching step, comprising: a leafsupport having an air-permeable leaf support top surface and a bottomsurface, retaining members cooperating with the leaf support to keep anarrow zone of a tobacco leaf in fixed position relative to the leafsupport, the airflow members being disposed over said top surface ofsaid leaf support and adapted to create within a first time intervalsaid airstream and a suction device cooperating with the bottom surfaceof the leaf support to suck within a second time interval air throughthe leaf support at least within a region corresponding to the size of atobacco leaf in order to retain by suction the stretched tobacco leaf onsaid top surface of the leaf support, said second time intervalbeginning approximately at the termination of the first time interval.

2. The apparatus as claimed in claim 1, characterized in that theairflow members consist of a box open against said top surface of theleaf support on which box two lateral edges opposed to one another andsubstantially parallel to said narrow zone are provided with air suctionopenings communicating during said first time interval with a vacuumsource, and in that the lid of the box is provided with air inletopenings located above said narrow zone.

3. The apparatus as claimed in claim 1 further comprising a first valvemeans for controlling the suction of air through the leaf support and asecond valve means for controlling the airstream in the airflow members.

4. The apparatus as claimed in claim 1, characterized in that the leafsupport consists of an endless, air-permeable driven belt support havings a width of least corresponding to the width of a stretched tobaccoleaf.

5. The apparatus as claimed in claim 4, characterized in that the beltis stretchable in its transverse direction.

6. The apparatus as claimed in claim 5, characterized in that thelongitudinal edges of the belt are provided with guide members runningin guide grooves along the two edges of the belt which guide grooveshave a first mutual spacing from one another before said first stationand another, greater spacing from one another behind said station,whereby an additional stretching of a tobacco leaf retained by suctionon the belt is accomplished.

7. The apparatus as claimed in claim 4, characterized in that the beltconsists of a stretchable, woven material.

8. The apparatus as claimed in claim 4, characterized in that the beltconsists of perforated rubber.

1. An apparatus for stretching and smoothing a natural tobacco leafincluding airflow members adapted to expose the leaf fixed on a leafsupport to an airstream directed from the central vein of the tobaccoleaf towards the edges thereof and suction members for retaining theleaf in expanded condition after the stretching step, comprising: a leafsupport having an air-permeable leaf support top surface and a bottomsurface, retaining members cooperating with the leaf support to keep anarrow zone of a tobacco leaf in fixed position relative to the leafsupport, the airflow members being disposed over said top surface ofsaid leaf support and adapted to create within a first time intervalsaid airstream and a suction device cooperating with the bottom surfaceof the leaf support to suck within a second time interval air throughthe leaf support at least within a region corresponding to the size of atobacco leaf in order to retain by suction the stretched tobacco leaf onsaid top surface of the leaf support, said second time intervalbeginning approximately at the termination of the first time interval.2. The apparatus as claimed in claim 1, characterized in that theairflow members consist of a box open against said top surface of theleaf support on which box two lateral edges opposed to one another andsubstantially parallel to said narrow zone are provided with air suctionopenings communIcating during said first time interval with a vacuumsource, and in that the lid of the box is provided with air inletopenings located above said narrow zone.
 3. The apparatus as claimed inclaim 1 further comprising a first valve means for controlling thesuction of air through the leaf support and a second valve means forcontrolling the airstream in the airflow members.
 4. The apparatus asclaimed in claim 1, characterized in that the leaf support consists ofan endless, air-permeable driven belt support having s a width of leastcorresponding to the width of a stretched tobacco leaf.
 5. The apparatusas claimed in claim 4, characterized in that the belt is stretchable inits transverse direction.
 6. The apparatus as claimed in claim 5,characterized in that the longitudinal edges of the belt are providedwith guide members running in guide grooves along the two edges of thebelt which guide grooves have a first mutual spacing from one anotherbefore said first station and another, greater spacing from one anotherbehind said station, whereby an additional stretching of a tobacco leafretained by suction on the belt is accomplished.
 7. The apparatus asclaimed in claim 4, characterized in that the belt consists of astretchable, woven material.
 8. The apparatus as claimed in claim 4,characterized in that the belt consists of perforated rubber.